The present invention relates generally to semiconductor devices and their fabrication and, more particularly, to semiconductor devices and their manufacture involving techniques for analyzing and debugging circuitry within an integrated circuit.
The semiconductor industry has recently experienced technological advances that have permitted dramatic increases in circuit density and complexity, and equally dramatic decreases in power consumption and package sizes. Present semiconductor technology now permits single-chip microprocessors with many millions of transistors, operating at speeds of hundreds of millions of instructions per second to be packaged in relatively small, air-cooled semiconductor device packages. The demand for increasing operating speed and decreasing package sizes continues to drive improvements in these areas, and continues to make semiconductor manufacturing processes more challenging.
As the manufacturing processes for semiconductor chips and integrated circuits increase in difficulty, methods for testing and debugging become increasingly important. Not only is it important to ensure that individual chips are functional, it is also important to ensure that batches of chips perform consistently. In addition, the ability to detect a defective manufacturing process early is helpful for reducing the number of defective chips manufactured.
Traditionally, semiconductor chips and integrated circuits have been tested using methods including directly accessing circuitry or devices within the chip or integrated circuit. In addition, many methods require the circuit to be powered. Directly accessing the circuitry is difficult for several reasons. For instance, in flip-chip type dies, transistors and other circuitry are located in a very thin epitaxially-grown silicon layer in a circuit side of the die. The circuit side of the die is arranged face-down on a package substrate. This orientation provides many operational advantages. However, due to the face-down orientation of the circuit side of the die, the transistors and other circuitry near the circuit side are not readily accessible for testing, modification, or other purposes. Therefore, access to the transistors and circuitry near the circuit side is from the back side of the chip.
Since access to the transistors and circuitry in flip-chips is generally from the back side of the chip, it is often necessary to mill through the back side and probe certain circuit elements in order to test the device. Milling through the back side is often difficult and time consuming. Moreover, circuitry and devices in the integrated circuit may potentially be damaged by milling processes. The difficulty, cost, and destructive aspects of existing methods for testing integrated circuits are impediments to the growth and improvement of semiconductor technologies.
The present invention is directed to a method and system for post-manufacturing analysis of a semiconductor chip involving real-time detection of emissions from the chip. The present invention is exemplified in a number of implementations and applications, some of which are summarized below.
According to an example embodiment of the present invention, a semiconductor chip is analyzed using an InGaAs camera coupled to an optical microscope. The chip has a back side opposite a circuit side, the back side includes silicon substrate, and the circuit side includes circuitry. A portion of the circuitry is excited and an emission such as a photoemission or a thermal emission is generated. The optical microscope coupled to the InGaAs camera is directed at the back side of the chip and used to obtain an image of the emission through the silicon substrate. The image is used for analysis of the semiconductor chip.
According to another example embodiment of the present invention, a system is adapted to analyze a semiconductor chip having a back side opposite a circuit side, wherein the back side includes silicon substrate and the circuit side includes circuitry. An excitation arrangement is adapted to excite a portion of the circuitry. A microscope arrangement is arranged over the chip and is adapted to obtain an image from the chip. An InGaAs camera arrangement is coupled to the microscope and is adapted to obtain and record the image data from the microscope arrangement.